Air conditioning system utilizing refrigeration



Aug. 31, 1937.

ELEc'rKI SOURCE R. 'r. PALMER 2,091,563 AIR CONDITIONING SYSTEMUTILIZING REFRIGERATION Filed March 15, 1936 3 Sheets-Sheet l MIXINGCHAMBER ELECTRIC sauce:

MIXING- CHAMBER Fl LTEZ Aug. 31, 1937. R T, PALMER 2,091,563

AIR CONDITIONING SYSTEM UTILIZING REFRIGERATION Filed March 13, 1936 3Sheets-Sheet 2 ELECTRIC SouzcE CHAMBER E LECTIZIO Sou BCE REFRIGERATIONSUPPLY Aug. 31, 1937. R. T. PALMER AIR CONDfTIONING SYSTEM UTILIZINGREFRIGERATION s Sheets-Sheet 13;

Filed March 13, 1936 for Mun

NOWWWNL Hp uowwwumtoo ZOO UUNDOW Q- NPOWAU muzwoqozm NNLIZDOO PatentedAug. 31, 1937 UNITED STATES PATENT OFFICE AIR CONDITIONING SYSTEMUTILIZING REFRIGERATION Robert T. Palmer, Sharon, Mass, assignor to B.F. Sturtevant Company, Inc., Boston, Mass.

Application March 13, 1936, Serial No. 68,657

15 Claims.

space within which the conditioned air is supplied.

According to this invention, the air volume, and the refrigeratingenergy is varied in accord- 15 ance with the number of people in thespace supplied with conditioned air. In one embodiment of the invention,a plurality of cooling coils extend, in the conditioner, cross-Wise theair stream, and the number of the active coils is. varied in accord- 20ance with load conditions. The inactive coils are shunted out of the airflow to reduce the resistance of the air through the conditioner, andthe air volume is reduced.

In one embodiment of the invention, the con- 25 trols of the airconditioning system are adjusted in accordance with the number ofpersons in the enclosure as determined by an actual count.

An object of the invention is to condition air at minimum expense.

30 Another object of the invention is to efficiently save fan power andrefrigerating energy in an air conditioning system, when the load isreduced.

Another obejct of the invention is to adjust the controls of an airconditioning system supplying 35 air to an enclosure, in accordance withthe number of persons in the enclosure as determined by actual count.

Other objects of the invention will be apparent from. the followingdescription taken together 40 with the drawings.

The invention will now be described with reference to the drawings, ofwhich:

' Fig. 1 is a diagrammatic view of one embodiment of the inventionutilizing several groups of a cooling coils in the conditioner; eachgroup of coils being served by a separate source of refrigeration;

Fig. 2 is a diagrammatic view of another em- 50 bodiment of theinvention in which all groups of air cooling coils are supplied by asingle source of refrigeration; and

Fig. 3 is a diagrammatic view ofanother embodiment of the invention inwhich controls are varied by a device which counts the actual number ofpersons in the space served with conditioned air.

With reference to Fig. 1, there is illustrated what is known as aby-pass system of the general type shown by the Patent No. 1,670,656 toW. L. 5

Fleisher. In the present case, the conditioner 5 has mounted therein,cross-wise the air stream, the three groups of evaporator coils, 6, land 8. The coils.6 are supplied through the expansion valve 9 with anysuitable refrigerant from com- 10 pressor #i and condenser #I. The coilsI are likewise supplied from compressor #2 and condenser #2, throughvalve 50, and the coils 8 are supplied through valve l I from compressor#3 and condenser #3. In front of, with respect to air how, of the coils6, are the shutters l2 adjusted to open or closed position by the motorI3. Similar shutters l4 adjusted by motor l5 are before the coils I, andsimilar shutters I6 adjusted by motor ll are before the coils 8.

The thermostat i8 is mounted in the path of the mixed recirculated andoutside air leaving the mixing chamber IS. The recirculated air from theenclosure 20 enters the mixing chamber I9 through the duct 2|, and theoutside air after '5 passing through the filter 22, enters the mixingchamber is through the duct 23.

The control thermostat I8 is seen to be responsive to the condition ofthe air to be conditioned.

In the past, it has been customary to place such control thermostats inthe space being conditioned or in the recirculated air duct, on thetheory that the load offered by the outdoor air is constant while theload within the space fluctuates to a great extent. In many cases,however, the load ofiered by the outside air has been found to fluctuatewhile the load offered by the recirculated air remains substantiallyconstant so that it is preferred to so mount the control thermostat isthat it responds to the changes in load of the total air entering theconditioner.

The thermostat i8 upon a decrease in the temperature of the air enteringthe conditioner 5, indicating that less refrigeration is required, actsfirst to open theenergizing circuit of the shutter control motor ll,causing it to close its associated shutters IS in front of tthe coils 8,as shown by the drawings. The suction temperature of the refrigerantentering the compressor #3 through the thermo-responsive valve 24, thenfalls, causing the thermostatic element within the valve 25 to open thecircuit including the motor 25, the solenoid 26, the wires .21, 28 and29, causing the compressor #3 to shut down.

At the same time, due to the deenergization of the solenoid 28, itsarmature falls to open a circuit including the fan driving motor 3|, the

wires 32 and 33, the contact 34, and an electric source disconnectingthe motor 3| from across 5 the line leading to the electric source. The

armature 38 then closes an electric circuit including the electricsource, the contact 35, the armature 36, the contact 31, the resistor 38and the fan motor 3|, thus connecting the fan motor in series with theresistor 38 to the electric source, causing the speed of the fan 39 andthe air volume it delivers, to be reduced. The fan then acts to draw areduced volume of mixed recirculated and outside air through the activecoils and 8, the inactive coils 8 offering no re-' sistance to the airflow.

If this reduction of cooling surface and air volume is not sufficient,the thermostat 8 next acts to open the energizing circuit of the shuttercontrol motor l5, causing it to close its associated shutters l6 infront of the coils l. The temperature of the refrigerant entering thecompressor #2 then falls causing the thermo-responsive valve 48 to opena circuit including the compressor driving motor 4|, the solenoid 42 andan energizing electric source, causing the compressor #2 to shut downand the solenoid 42 to become deenergized, this latter causing thearmature 36 to fall to open the previously described circuit includingthe contact 31 and resistor 38, and to close a circuit including thecontact 43, the resistor 44, the resistor 38 and the fan motor 3 I. Thisconnects the fan motor 3| in series with both resistors 44 and 38causing another reduction in fan speed and volume.

When, as in the case of an outdoor temperature drop, the above describedreductions in cooling surface and air volumes are insuflicient, thethermostat l8 opens the energizing circuit of the shutter control motorl3 causing it to close its associated shutters I2 in front of the coils6 and to open the shutters 45 in a by-pass through the conditioner 5around all of the coils. The resulting drop in the temperature of therefrigerant enter- 45 ing the compressor #1 through thethermo-responsive valve 46 causes it to open the energizing circuit ofthe compressor driving motor 41 to shut down the compressor #l.

The system then operates automatically as a 50 ventilating system untila change in the temperature of the outside or of-the recirculated airindicates that refrigeration is required, following which the thermostatwill act to place the requisite cooling surface intoservice and toregulate the fan volume accordingly.

During the operation 'of the system as described in the foregoing,by-pass air enters through the duct 48, the mixing chamber 48 at theoutput side of the conditioner 5, and serves to raise the sensible heatof the air leaving the conditioner.

No damper adjustment of the by-pass air is necessary due to the factthat its volume varies in accordance with the total air volume and theeffective coil surface, so that at all times the system is in balance.

The embodiment of the invention illustrated by Fig. 2 is essentially thesame as that described above in connection with Fig. 1, except that asingle source of refrigeration, which may be an indirect source,supplies refrigeration to all three groups of air cooling coils, and nothermostat such as control thermostat I8 01 Fig. 1 is used.

The coils themselves determine the amount of cooling surface and airvolume required. If when all coils are in service, the refrigerantreturned to the source shows by arriving at too low a temperature, thatthe maximum cooling effect is not required, first one and then theothers of the groups of coils are rendered inactive. Most of theapparatus is similar to that shown by Fig. 1 so that the same referencecharacters will be applied to apparatus common to both figures.

The refrigeration supply 58 supplies a cooling liquid through the pipeto the coils 6, 1 and 8 which are in series with respect to fluid flowwhen all are in service. Between coils 6 and 1 is the two way valve 52which may be adjusted by the solenoid 53 to close off the entrance ofthe liquid to the coils 1 and to return it through the pipe 54 to thesupply 58. Between coils I and 8 is a similar valve 55 which maybeadjusted by the solenoid 56 to close off the entrance of the fluid tothe coils 8 and to return the fluid leaving coils l to the supply 58,through the pipe 51. Normally, when all of the coils are active, therefrigerant passes through all coils and returns to the source 58through pipe 58.

In the common return pipe 59 to the source 58 are mounted thethermostats 68 and 6|. With all three groups of coils 6, 1 and 8 active,when the load on the coils is such that their total effect is notnecessary, this is indicated by too low a tem perature of therefrigerant passing first through the thermostat 68, on its return tothe source 58. This causes the thermostat 68 to open a circuit includingthe electric source, the solenoid 26, the shutter control motor I! andthe solenoid 56, causing the solenoid 56 to adjust the valve 55 toby-pass the refrigerant around the coils 8; causing the motor I! toclose its associated shutters I 6, and causing the solenoid 26 toconnect the resistance 38 in the circuit of the fan motor 3|, asdescribed in connection with Fig. 1, to decrease the fan speed'andvolume.

If this reduction is not sufficient, the thermostat 6| responds to opena circuit including the electric source. the solenoid 42, the shuttercontrol motor l5, and the solenoid 53. This causes the solenoid 53 toadjust the valve 52 to by-pass the refrigerant around the coils 1;causes the motor I5 to close the shutters l4 before the coils 1, andcauses the solenoid '42 to close a circuit to connect resistors 44 and38 in the circuit of the fan motor 3| as described above in connectionwith Fig. 1.

If this reduction is not sufficient, the thermostat 62 in the enclosure28 opens a circuit including the motor 63 of the refrigeration supply,to discontinue the supply of refrigeration to the coils, and includingthe shutter control motor l3 causing it to close the shutters |2 infront of the coils 6. At.-the same time, the motor l3 opens the shutters45 to enable ventilating air to bypass the coils in the conditioner 5.When the temperature within the enclosure 28 rises above the setting ofthe thermostat '62, it functions to supply refrigeration to the coils 6.If this is not sufficient, the thermostat 68 places the coils 8 inservice.

The embodiment of the invention illustrated by Fig. 3 is similar to thatdescribed above in connection with Fig. 1 except that no shutters areplaced in front of the coils 6; no by-pass in the conditioner around thecoils is provided, and

a device which determines the number of persons in the enclosure 28,adjusts the volume of outside air in proportion to the number of personsin the enclosure. The remainder of the apparatus and its method ofoperation are similar to ping the compressor that-illustrated by Fig. 1so that the same reference characters are used for this apparatus commonto Figs. 1 and 3.

In the fresh outside air inlet duct 23 are mounted the dampers 64adjustable by the solenoid 65 from one third open to wide openpositions. The current supply to the solenoid 65 and to the shuttercontrol motors l5 and I1 is controlled by the counting mechanism whichwill now be described.

As illustrated no occupants are in the enclosure 28 and the system isrunning at minimum capacity with only the coils 8 and compressor #Iactive; with the outside air'damper 64 two thirds closed, and the fan 39operating at one third volume. During this period of minimum load, thethermostat 63 in the recirculated air duct 2i, controls the conditioner5 by starting and stop- Persons entering the enclosure 20 pass in theentrance 86 in single file and in so doing interrupt the light beam fromthe light source 6'! to the photo-electric cell '68. The currentimpulses in the cell 68 are amplified by the amplifier 69 and are thenfed into the counter 18 which may be similar to those disclosed byPatent Re. 18,567, issued August 9, 1932 to R. J. Wensley et al., andwhich as the impulses accumulate, rotate the gear II, in mesh with thegear 12, which is threaded internally to mesh with the threads on theshaft 13 so that the shaft 13 on which is mounted the resistor 14 movesfrom left to right (facing the drawing) as the number of people enteringthe enclosure 20 increases. During the movement of the shaft 13 andresistor M, the contact 15 moves across the face of the resistor M todecrease the resistance of and increase the current flow in, theenergizing circuit of the armature coil 16 of the galvanometer indicatedgenerally by 11.

During this time, any persons leaving the enclosure 20, pass in singlefile through the exit I8 and in so doing, interrupt the light beambetween the source '59 and the photo-electric cell 88, causing currentimpulses 'to be amplified in the amplifier 8i and to flow into thecounter 82, similar to the counter 10, but rotating in the oppositedirection to tend through the action of the gears 83 and 84 to move theshaft 13 and resistor M to the left (facing the drawing), thus tendingto increase the resistance in the energizing circuit of the galvanometercoil 16. When a person enters and another person leaves the enclosure atthe same time, the counters 10 and 82 oppose each other and the resistordoes not move. As more persons enter than leave the enclosure 20, theresistance in the energizing circuit of the galvanometer coil 16 isdecreased to cause the coil 16 and its contact arm 85 to move to theright (facing the drawing) in proportion to the decrease in resistance,which in turn is proportional at any time, to the number of persons whohave entered the enclosure 20 and have not left.

As the number of persons in the enclosure 20 increases, the coil 18moves the arm 85 to the right (facing the drawing), and the contact 86is moved across the resistance 81 to decrease the value of theresistance in the energizing circuit of the solenoid 65, causing it tomove its damper 64 towards open position, proportional to the number ofpersons in the enclosure.

When the persons. in the enclosure 20 have increased to a predeterminednumber, the arm 85 moves against the contact segment 88 closing theenergizing circuit of the shutter control motor the shutter controlmotor l5, causing it to become energized to adjust the shutters I4,before the coils I to open position. The thermostat 40 then causes thecompressor #2 to start up.

When the persons in the enclosure have further increased to a largerpredetermined number, the contact arm tact segment 89 to close theenergizing circuit of H causing it to adjust its shutters l6, before thecoils 8, to open position. The thermostat 24 then places the compressor#3 into operation.

The thermostat '83 in the recirculated air duct 2| acts to prevent toocold air from being supplied into the enclosure 20 by shutting down thecompressor #I when the recirculated air indicates that too much coolingis being done in the conditioner. This has the double effect ofdecreasing the refrigeration effect, and of increasing the by-pass aireffect due to the relatively high temperature untreated air passingthrough the now inactive coils 6 to mix with and raise the sensible heatof the air passing in contact with the active coils.

The speed and volume of the fan 39 is automatically increased by theaction of the relays 26 and 42, when the coils I and 8 are placed inservice, so as to vary the total volume of air passing through theconditioner in accordance with the load within the enclosure 20. Thevolume of fresh air is varied by the adjustment of the fan 39 when thetotal volume handled by the fan is adjusted, but the proportion of freshair to recirculated air is adjusted by the damper 85 which also, ofcourse, varies the total volume of fresh air entering the conditioner.

A volume of exhaust air equal at all times to that of the outsidemake-up air admitted into the conditioner, is vented from the enclosurethrough outlets which may be special exhaust outlets or which may be theever present cracks and crevices.

While the means for the control of volume of the fan has beenillustrated as a speed control means, it is obvious that the volume maybe regulated by adjustment of spin inducing vanes in the fan inlet. Forexample, fans provided With control vanes such as are disclosed by thePatents No. 1,846,863, or No. 1,989,413 to H. F. Hagen may be had withautomatic adjusting mechanism such as disclosed in application Ser. No.81,455 filed May 23, 1936.

Whereas several embodiments of the invention have been described for thepurpose of illustration. it should be understood that the invention isnot to be limited to the exact arrangement described, as many departuresmay be made by those skilled in the art, after having had access to thisdisclosure.

What is claimed is:

1:. Air conditioning apparatus comprising a plurality of air coolers,means for supplying refrigerant to said coolers, a. fan for passing astream of air through said coolers and into a room to be supplied withconditioned air, and means responsive to a function of the psychrometriccondition of the air in said room for varying the volume of air moved bysaid fan and the number of said coolers exposed to said air stream.

2. Air conditioning apparatus comprising a plurality of air coolers,means for supplying refrigerant to said coolers, a fan for passing astream of air through said coolers and into a room to be supplied withconditioned air, and

85 moves against the conmeans responsive to a function of thepsychrometric condition of the air in said room for varying the volumeof air moved by said fan, the number of said coolers supplied withrefrigerant,

5 and the number of said coolers exposed to said air stream.

3. Air conditioning apparatus comprising an air cooling chamber, aplurality of groups of air cooling coils in said chamber, a fan forpassing 10 a stream of air through said chamber and for discharging itinto a roomto be supplied with conditioned air, means for selectivelysupplying said groups of coils with refrigerant, and means responsive tothe temperature of one of said 15 groups of coils for varying the numberof said groups of coils to be supplied with refrigerant.

4. Air conditioning apparatus comprising a plurality of air coolers, afan for passing a stream of air through said coolers and for discharging20 it into a room to be supplied with conditioned air, means forselectively supplying said coolers with refrigerant, and meansresponsive to the temperature of the refrigerant returned to said lastmentioned means for varying the number of 25 said coolers to be suppliedwith refrigerant.

5. Air conditioning apparatus comprising an air cooling chamber, aplurality of groups of air cooling coils in said chamber, a fan forpassing a stream of air through said chamber and for 30 discharging itinto a room to be supplied with conditioned air, means for selectivelysupplying said groups of coils with refrigerant, and means responsive tothe temperature of the refrigerant returned to said last mentioned meansfor varying the number of said groups of coils to be supplied withrefrigerant.

6. Air conditioning apparatus comprising a plurality of coolers, a fanfor passing a stream of air through said coolers and for discharging 40it into a room to be supplied with conditioned air, means forselectively supplying said coolers with refrigerant, means responsive tothe temperature of the refrigerant returned to said last mentioned meansfor varying the number of. said 45 coolers to be supplied withrefrigerant, and for removing the ineffective coolers from said airstream.

7. Air conditioning apparatus comprising in combination a room to besupplied with condi- 50 tioned air, an air cooling chamber, air coolingmeans in said chamber, a fan for moving air through said chamber and fordischarging it into said room, means for supplying refrigerant to saidair cooling means, means for determining the approximate number ofpeople in said room, and means including said last mentioned means forcontrolling the conditioning of the air by said apparatus.

8. Air conditioning apparatus comprising in 60 combination a room to besupplied with conditioned air, an air cooling chamber, air cooling meansin said chamber, means for supplying outside air into said chamber forconditioning, a fan for moving air through said chamber and for 65discharging it into said room, means for supplying refrigerant to saidair cooling means, means for determining the approximate number ofpeople in said room, and means including said last mentioned means forvarying the volume 7 of outside air entering said chamber.

9. Air conditioning apparatus comprising in combination a room to besupplied with conditioned air, an air cooling chamber, air cooling meansin said chamber, means for supplying 75 outside air into said chamberfor conditioning,

a fan for moving air through said chamber and for discharging it intosaid room, means for supplying refrigerant to said air cooling means,means for determining the approximate number of people in said room, andmeans including said last mentioned means for varying the volume ofoutside air entering said chamber, and the supply of refrigerant to saidair cooling means.

10. Air conditioning apparatus comprising in combination a room to besupplied with condi- 10 tioned air, an air cooling chamber, air coolingmeans in said chamber, means for supplying outside air into said chamberfor conditioning, a fan for moving air through said chamber and fordischarging it into said room, means for supplying refrigerant to saidair cooling means, means for determining the approximate number ofpeople in said room, and means including said last mentioned means forvarying the volume of outside air entering said chamber, the supply ofrefrigerant to said air cooling means, and the total volume of airsupplied by said fan into said room.

11. Air, conditioning apparatus comprising in combination a room to besupplied with conditioned air, a plurality of air coolers, means forsupplying outside air to said coolers for conditioning, a fan for movingair through said coolers and for discharging it into said room, meansfor supplying refrigerant to said coolers, means for determining theapproximate number of people in said room, and means including said lastmentioned means for varying the volume of outside air entering saidchamber, and the number of said coolers in contact with said air stream.

12. Air conditioning apparatus comprising in combination a room to besupplied with conditioned air, an air cooling chamber, a plurality ofgroups of air cooling coils in said chamber, means for supplying outsideair into said chamber for conditioning, a fan for moving air throughsaid chamber and for discharging it into said room, means for supplyingrefrigerant to said air cooling means, means for determining theapproximate number of people in said room, and means including said lastmentioned means for varying the volume of outside air entering saidchamber, the number of said groups of coils in contact with the airstream through said chamber, and ,for controlling the supply ofrefrigerant to said coils.

13. Air conditioning apparatus comprising in combination, an enclosureto be supplied with conditioned air, a conditioning unit, means forsupplying conditioned airfrom said unit into said enclosure, means forsupplying fresh air into said unit, counting means for determining theapproximate number of occupants of said enclosure, said last mentionedmeans including totalizing means for adding increases andfor subtractingdecreases in the approximate number of occupants, and means utilizingsaid totalizing means for varying the volume of fresh air in accordancewith the number of occupants of said enclosure.

14. Air conditioning apparatus comprising in combination, an enclosureto be supplied with conditioned air, a conditioning unit, means forsupplying conditioned air from said unit into said enclosure, means forsupplying fresh air into said unit, means for supplying air recirculatedfrom said enclosure into said unit, counting means for determining theapproximate number of occupants of said enclosure, said last mentionedmeans including totalizing means for adding increases and forsubtracting decreases in the approximate number of occupants, and meansutilizing said totalizing means for varying volumes of fresh andrecirculated air substantially in accordance with changes in the numberof occupants of said enclosure.

15. Air conditioning apparatus comprising in combination, an enclosureto be supplied with conditioned air, a conditioning unit, means forsupplying air recirculated from said enclosure into said unit forconditioning, means for supplying fresh air into said unit, means forsupplying air recirculated from said enclosure as bypass air, to theoutput side of said unit, counting means for determining the approximatenumber of occupants of said enclosure, said last mentioned meansincluding totalizing means for adding increases and for subtractingdecreases in the approximate number of occupants, and means utilizingsaid totalizing means for varying the volumes of fresh air, recirculatedair, and bypass air as changes in the number of occupants of saidenclosure take place.

ROBERT T. PALMER.

